The invention is directed towards the formation of polymers and copolymers using late transition metal polymerization catalyst complexes which are formed in situ.
Polymers and copolymers may be formed from olefinic monomers by using organometallic catalyst technology. Commonly used organometallic catalysts include Ziegler-Natta catalysts and metallocene catalysts. Despite the technological and commercial success of Group 4 (Ti and Zr) Ziegler-Natta and metallocene catalysts for polyolefins, the search for new catalysts and polymerization techniques continue. More specifically, the chemical industry strives to obtain even greater control over product properties and extend the family of products to new monomer combinations. Catalysts that tolerate a variety of functional groups are of particular interest because they not only open up new product possibilities, but also allow the use of cheaper, less pure monomer feeds. To this end, late transition metals are generally more tolerant of polar groups than the early transition metals.
Late transition metal catalysts have been used to a limited degree in polymerization processes. Many of these processes use free radical techniques and preformed catalyst complexes. Other techniques such as atom transfer radical polymerization (xe2x80x9cATRPxe2x80x9d) utilize an initiator such as an alkyl halide, a Group 11 metal compound such as CuCl, and an amine such as 2,2xe2x80x2-dipyridine as taught by Matyjaszewski in WO96/30421, herein incorporated by reference. The ATRP process uses an initiator in lieu of a cocatalyst (e.g., methyl alumoxane, a.k.a. xe2x80x9cMAOxe2x80x9d). The amine in ATRP is used to solubilize the metal compound in media. Furthermore, ATRP is known to polymerize only styrene and acrylates and is not known to polymerize other monomers such as ethylene.
Recently, novel late transition organometallic catalysts have been developed which are useful in forming polymers and copolymers having hydrocarbyl polar functionality. More specifically, U.S. Pat. No. 6,037,297 to Stibrany et al., herein incorporated by reference, details group 11 (Cu, Ag and Au) containing catalyst compositions having a pseudotetrahedral geometry. The polymerization technique disclosed in U.S. Pat. No. 6,037,297 teaches the preparation of a solid and isolated complex. The complex is a single compound that can be put in the container and stored on the bench top. Such a complex would not yet be considered an active catalyst by one skilled in the art. For the complex to be used as a catalyst for polymerization, the complex must be mixed with an activating cocatalyst, such as MAO, to create an activated catalyst which can be used to polymerize monomers. Thus, there are two discrete steps which are undertaken to create the active polymerization catalyst which makes the production of polymers and copolymers less efficient and more expensive.
Hence, there is still a need to improve the efficiency of processes for catalyst formation and polymerization. Additionally, processes which allow the incorporation of polar monomer groups are advantageous.
The instant invention provides a novel olefin polymerization process based on the use of a group 11 transition metal halide, a nitrogen containing ligand such as a bis-benzimidazole, and an activating cocatalyst (e.g., MAO) which form an activated catalyst composition in situ. This activated catalyst composition is then used to polymerize olefins and copolymerize olefins with polar monomers. Unlike ATRP, the instant invention does not use an alkyl halide initiator but instead uses a cocatalyst. Further, unlike U.S. Pat. No. 6,037,297, the invention teaches that use of a preformed metal complex is not a prerequisite. More specifically, the metal complex may be formed in-situ by adding the metal compound with a ligand at the same time cocatalyst is added. Hence, the advantages of the instant invention include an in situ method for forming an active catalyst composition which is a step-saving, cost-saving process. The invention also provides a method for polymerizing olefins as well as copolymers having polar monomers incorporated therein.
In one embodiment, the invention provides a method for producing an activated catalyst composition in situ and producing polymers therefrom comprising the steps of: (a) simultaneously contacting a composition having the formula MXZn with L and an activating cocatalyst; wherein M is selected from the group consisting of Cu, Ag, and Au; X is selected from the group consisting of halides, hydride, triflate, acetates, borates, C1 through C12 alkyl, C1 through C12 alkoxy, C3 through C12 cycloalkyl, C3 through C12 cycloalkoxy, aryl, thiolates, carbon monoxide, cyanate, olefins, and any other moiety into which a monomer can insert; Z is selected from the group consisting of halides, hydride, triflate, acetates, borates, C1 through C12 alkyl, C1 through C12 alkoxy, C3 through C12 cycloalkyl, C3 through C12 cycloalkoxy, aryl, thiolates, carbon monoxide, cyanate, olefins, a neutral coordinating ligand, and any other moiety into which a monomer can insert; n equals 0, 1 or 2; L is selected from the group consisting of monodentate nitrogen-containing ligands and bidentate nitrogen-containing ligands; and, (b) contacting olefinic monomers under polymerization conditions; wherein said olefinic monomers are selected from the group consisting of acyclic aliphatic olefins, olefins having a hydrocarbyl polar functionality, mixtures of olefins having at least one olefin with a hydrocarbyl functionality and at least one acyclic aliphatic olefin; whereby polymers or copolymers are formed.
These and other features, aspects and advantages of the present invention will become better understood in view of the following description and claims.
In one embodiment, the invention provides a method for producing an activated catalyst composition in situ and producing polymers or copolymers therefrom. It should be appreciated by those skilled in the art that use of the general term xe2x80x9ccopolymersxe2x80x9d includes terpolymers and other polymers having various combinations of different monomer units.
In the first process step of the instant invention, a composition having the formula MXZn is simultaneously contacted with L and an activating cocatalyst. Referring to the formula, M is selected from the group consisting of Cu, Ag, and Au; X is selected from the group consisting of halides, hydride, triflate, acetates, borates, C1 through C12 alkyl, C1 through C12 alkoxy, C3 through C12 cycloalkyl, C3 through C12 cycloalkoxy, aryl, thiolates, carbon monoxide, cyanate, olefins, and any other moiety into which a monomer can insert; Z is selected from the group consisting of halides, hydride, triflate, acetates, borates, C1 through C12 alkyl, C1 through C12 alkoxy, C3 through C12 cycloalkyl, C3 through C12 cycloalkoxy, aryl, thiolates, carbon monoxide, cyanate, olefins, a neutral coordinating ligand, and any other moiety into which a monomer can insert; n equals 0, 1 or 2; and L is selected from the group consisting of monodentate nitrogen-containing ligands and bidentate nitrogen-containing ligands.
In a subsequent process step of the instant invention, olefinic monomers are contacted with the activated catalyst composition under polymerization conditions. The olefinic monomers are selected from the group consisting of acyclic aliphatic olefins, olefins having a hydrocarbyl polar functionality, mixtures of olefins having at least one olefin with a hydrocarbyl polar functionality and at least one acyclic aliphatic olefin. Polymers and copolymers are thereby formed.
Examples of the activating cocatalysts used above include, but are not limited to, aluminum compounds containing an Alxe2x80x94O bond such as the alkylalumoxanes such as methylalumoxane (xe2x80x9cMAOxe2x80x9d) and isobutyl modified methylalumoxane; aluminum alkyls; aluminum halides; alkylaluminum halides; Lewis acids other than any of the foregoing list; and mixtures of the foregoing can also be used in conjunction with alkylating agents, such as methyl magnesium chloride and methyl lithium. Examples of such Lewis acids are those compounds corresponding to the formula: Rxe2x80x3xe2x80x33B, wherein Rxe2x80x3xe2x80x3 independently each occurrence is selected from hydrogen, silyl, hydrocarbyl, halohydrocarbyl, alkoxide, aryloxide, fluoroaryl, amide or combinations thereof, said Rxe2x80x3xe2x80x3 having up to 30 non-hydrogen atoms.
It is to be appreciated by those skilled in the art, that the above formula for the preferred Lewis acids represents an empirical formula, and that many Lewis acids exist as dimers or higher oligomers in solution or in the solid state. Other Lewis acids which are useful in the catalyst compositions of this invention will be apparent to those skilled in the art.
Other examples of such cocatalysts include salts of group 13 element complexes. These and other examples of suitable cocatalysts and their use in organometallic polymerization are discussed in U.S. Pat. No. 5,198,401 and PCT patent documents PCT/US97/10418 and PCT/US96/09764, all incorporated by reference herein.
Preferred activating cocatalysts include trimethylaluminum, triisobutylaluminum, methylalumoxane, ethylalumoxane, chlorodiethyaluminum, dichloroethylaluminum, triethylboron, trimethylboron, triphenylboron and halogenated, especially fluorinated, triphenyl boron compounds.
Most highly preferred activating cocatalysts include triethylaluminum, methylalumoxane, and fluoro-substituted triaryl borons such as tris(4-fluorophenyl)boron, tris(2,4-difluorophenylboron), tris(3,5-bis(trifluoromethylphenyl) boron, tris(pentafluorophenyl) boron, pentafluorophenyl-diphenyl boron, and bis(pentafluorophenyl) phenylboron. Such fluoro-substituted triarylboranes may be readily synthesized according to techniques such as those disclosed in Marks, et al., J. Am. Chem. Soc., 113, 3623-3625 (1991) which is herein incorporated by reference.
In a preferred embodiment, the activating cocatalyst is selected from the group consisting of alkylalumoxanes, aluminum alkyls, aluminum halides, alkyl aluminum halides, Lewis acids other than any of the foregoing, alkylating agents and mixtures thereof. Most preferably, the cocatalyst is methyl alumoxane.
Furthermore, the equivalent ratio of metal complex to activating cocatalyst is preferably in a range from 1:0.5 to 1:104, more preferably from 1:0.75 to 1:103. In most polymerization reactions the equivalent ratio of catalyst:polymerizable compound employed is from 10xe2x88x9212: to 10xe2x88x921:1, more preferably from 10xe2x88x929:1 to 10xe2x88x924:1.
In another preferred embodiment, L is a nitrogen containing ligand selected from the group consisting of aromatic compounds and aliphatic compounds. Examples of nitrogen containing aromatic compounds include, but are not limited to, heterocycles such as a monodentate and bidentate ligands like a substituted or unsubstituted pyridine, aniline, pyrrole, imines, imidazoles, benzimidazoles, pyrazoles, oximes; and bipyridine. Examples of such compounds are shown below: 
For the structures above, each R is independently selected from the group consisting of alkyl, cycloalkyl, and aromatic groups which optionally contain heteroatoms. Note that although only one or two R groups are shown above, there could be as many as 10 or more depending upon the size of aromatic rings.
Specific examples of nitrogen containing aromatic compounds include pyridine, 2,6-di-tert-butylpyridine, 2,2xe2x80x2-bipyridine, 4,4xe2x80x2-dimethyl-2,2xe2x80x2-bipyridyl, 4,4xe2x80x2-dimethyl-2,2xe2x80x2-bipyridyl, 5,5xe2x80x2-dimethyl-2,2xe2x80x2-bipyridyl, 6,6xe2x80x2-tert-butyl-2,2xe2x80x2-dipyridyl, 4,4xe2x80x2-diphenyl-2,2xe2x80x2-bipyridyl, 1,10-phenanthroline, 2,7-dimetyl-1,10-phenanthroline, 5,6-dimetyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline and 2,9-dimetyl-4,7-diphenyl-1,10-phenanthroline, 1,1xe2x80x2-bis(1-methylbenzimidazol-2-yl)-1xe2x80x3-methoxyethane, 3,3xe2x80x2-(1-ethylbenzimidazol-2-yl)-pentane, 2,2xe2x80x2-bis{2-(1-alkylbenzimidazol-2-yl)}biphenyl, 2,2xe2x80x2-bis(1-octylbenzimidazole-2yl)biphenyl, and 3,3xe2x80x2-bis(1-butylbenzimidazol-2yl)1xe2x80x3-pentane.
Examples of aliphatic amines include, but are not limited to, substituted and unsubstituted ethylenediamine, 2,2xe2x80x2-bipiperidine, and similar structures. Examples of these types of compounds include those having the following structures: 
where R is independently selected from the group consisting of hydrogen, C1 to C20 alkyl; cycloalkyl, and aromatic groups which optionally contain heteroatoms. In case of ethylenediamine and propylenediamine, both may be substituted from one to four times on the amino nitrogen atom with a C1 to C4 alkyl group. Specific examples of nitrogen containing aliphatic compounds include N,N,Nxe2x80x2,Nxe2x80x2-tetramethylethylenediamine, N,N,Nxe2x80x2,Nxe2x80x2-tetraethylethylenediamine, N,N,Nxe2x80x2,Nxe2x80x2-tetraethyl-1,3-propanediamine, N,Nxe2x80x2-di-tert-butylethylenediamine, N,Nxe2x80x2-dibutyl-1,6-hexanediamine, N,N-dibutyl-1,3-propanediamine, N,Nxe2x80x2-diethylethylenediamine, N,Nxe2x80x2-diphenylethylenediamine and 1,4-diazabicyclo[2,2,2]octane.
Olefinic monomers useful in the forming homo and copolymers with the catalyst of the invention include, for example, ethylenically unsaturated monomers, nonconjugated dienes, and oligomers, and higher molecular weight, vinyl-terminated macromers. Examples include C2-20 olefins, vinylcyclohexane, tetrafluoroethylene, and mixtures thereof. Preferred monomers include the C2-10 xcex1-olefins especially ethylene, propylene, isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene or mixtures of the same.
Monomers having hydrocarbyl polar functionalities useful in forming homo and copolymers with the catalyst of the invention, are vinyl ether and C1 to C20 alkyl vinyl ethers such as n-butyl vinyl ether, acrylates, such as C1 to C24, or alkyl acrylates such as t-butyl acrylate, and lauryl acrylate, as well as methacrylates such as methyl methacrylate.
In general, the polymerization may be accomplished at conditions well known in the prior art for Ziegler-Natta or Kaminsky-Sinn type polymerization reactions, that is, temperatures from xe2x88x92100xc2x0 C. to 250xc2x0 C. preferably 0xc2x0 C. to 250xc2x0 C., and pressures from atmospheric to 1000 atmospheres (100 Mpa). Suitable polymerization conditions include those known to be useful for metallocene catalyst when activated by aluminum or boron-activated compounds. The polymerization typically will be conducted in the presence of a solvent. Further, the polymerization will be conducted for a time sufficient to form the polymer and the polymer is recovered by techniques well known in the art and illustrated in the examples hereinafter.
Additionally, suspension, solution, slurry, gas phase or other process conditions may be employed if desired. The catalyst may be supported and such supported catalyst may be employed in the polymerizations of this invention. Preferred supports include alumina, silica, mesoporous materials, and polymeric supports.
The invention is further described in the following non-limiting examples.